View Full Version : Question: "Muzzle Energy" vs. "Power Factor"
All,
I'm having trouble understanding what's more important -- "muzzle energy" (i.e. kinetic energy1) vs. "power factor" (i.e. momentum2).
MUZZLE ENERGY
Most of the reading I've done focuses on energy as the determining factor in the lethality of a given caliber/round. Thus, the conventional wisdom is that you need a minimum of 1,000 foot-pounds of energy to kill a deer and 3,000 foot-pounds to kill a brown bear, etc. But since energy places a lot of emphasis on speed, you can come up with some pretty ridiculous examples.
Jellyfish: The stinger of a jellyfish is one of the fastest things in nature3. If you do the calculations, a 0.50 nanogram jellyfish stinger traveling at 45,000,000 meters/second = 0.0000000077 grains at 147,637,795.28 feet/second = 373.38 foot-pounds of energy
Bowling Ball: At the other end of the spectrum, you have world record holders who can throw a 15 pound bowling ball at 27 miles/hour4 = 105,000 grains at 39.60 feet/second = 365.53 foot-pounds of energy
Comparable "muzzle energy", but what would you rather have hurled at you? A microscopic needle or a 15 pound projectile? Now let's look at bullets.
9x19mm: 115 grain Winchester FMJ bullet traveling at 1,190 feet/second5 = 361.53 foot-pounds of energy
.45 ACP: 230 grain Winchester FMJ bullet traveling at 835 feet/second6 = 356.00 foot-pounds of energy
Again, similar muzzle energy, but which has the better reputation for "knock down"?
POWER FACTOR
If we switch from energy to momentum, the numbers above change drastically:
Jellyfish: The super fast but super light stinger has a power factor of 0.0011 kilo grain-feet/second (or 0.000023 Newton-seconds)
Bowling Ball: The super slow but super heavy bowling ball has a power factor of 4,158 kilo grain-feet/second (or 82.12 Newton-seconds)
Makes sense, right? A nanogram thrown at you -- even very very very fast -- ain't gonna do much to you, but a 15 pound bowling ball hurled at 27 miles/hour towards your face is going to hurt. And comparing bullets:
9x19mm: power factor of 136.85 kilo grain-feet/second (or 2.70 Newton-seconds)
.45 ACP: power factor of 192.05 kilo grain-feet/second (or 3.79 Newton-seconds)
Again, makes sense: .45 is perceived as having more stopping power than 9mm.
QUESTION
So is muzzle energy still the king?
If so, why is .308 Winchester (~2700 ft-lbs) considered inadequate for large predators (e.g. grizzly):
https://www.m4carbine.net/showthread.php?151658-308-for-Grizzly
But .458 SOCOM (~2500 ft-lbs) is considered good to go?
https://www.m4carbine.net/showthread.php?79391-How-s-458-SOCOM-For-Big-Bear-Defense
Is it the greater power factor of .458 (600 kgr-ft/s) vs .308 (463 kgr-ft/s)? Or is it something else -- sectional density? Bullet weight and diameter? Expansion and penetration? What am I missing here?
Taylor has one answer:
https://en.wikipedia.org/wiki/Taylor_KO_Factor
Looking for additional insight from the experts here at m4carbine.net
Respectfully,
butlers
FOOTNOTES
1 Source:
https://en.wikipedia.org/wiki/Muzzle_energy
2 Source:
https://en.wikipedia.org/wiki/Power_factor_(shooting_sports)
3 Sources:
https://www.sciencedaily.com/releases/2006/05/060508180735.htm
https://www.popsci.com/jellyfish-syringe-sting
4 Source:
https://www.bowlingdigital.com/bowl/node/14269
5 Source:
https://www.luckygunner.com/winchester-9mm-ammo-100-rounds-of-115-grain-fmj-ammunition
6 Source:
https://www.luckygunner.com/winchester-45-acp-ammo-for-sale-45acp230fmjwinusa-500
Simplified:
The ability of a projectile to penetrate into and sufficiently damage the vital organs of the intended target is paramount. Expansion is a great bonus.
Do a search for "IWBA" (international Wound Ballistics Association), as well as Martin L. Fackler M.D. and Gary K. Roberts LCDR.
This will get you started on the appropriate track in understanding wound ballistics.
Your welcome....
Neither is the short answer. It sure would be nice if some math could explain it all, nice and tidy but unfortunately it doesn't. The way the bullet acts is going to play a huge role in the wound created.
Here is another search to try: Basic Wound Ballistic Terminal Performance Facts
Its important to note that Power Factor is used to give .40 and .45 cal guns a scoring advantage in competition (USPSA) that makes up for their recoil disadvantage. Gives them an edge in scoring, in my opinion, which is why my Limited gun is a .40, and my carry guns are mostly 9mm. Has no bearing on the ability to incapacitate mammals.
Neither by themselves gives any indication of a bullets terminal performance.
vicious_cb
08-28-18, 00:36
Neither mean anything in terms of a bullet's ability of incapacitate.
Both examples you quote are about equal. Once you get about 500 FPE with an expanding or partially fragmenting bullet things get interesting. Some people are still mystified as to why a 357 magnum is so much more effective than a 38 Special when they use the same bullet, the magnum moves about 500 fps faster which effectively doubles the energy. It is, I think the best example that explains the phenomenon in easy terms.
Bullet construction is just as important as "energy".
Street results for the 357 Sig are very promising, as are the results of the +P+ 9mm.
The big problem is that too many people worry too much about their ammo and not enough about mastering their gun so that they can get consistent hits.
Both examples you quote are about equal. Once you get about 500 FPE with an expanding or partially fragmenting bullet things get interesting. Some people are still mystified as to why a 357 magnum is so much more effective than a 38 Special when they use the same bullet, the magnum moves about 500 fps faster which effectively doubles the energy. It is, I think the best example that explains the phenomenon in easy terms.
Bullet construction is just as important as "energy".
Street results for the 357 Sig are very promising, as are the results of the +P+ 9mm.
The big problem is that too many people worry too much about their ammo and not enough about mastering their gun so that they can get consistent hits.
Can you share what +p+ 9mm loads have good street results?
Can you share what +p+ 9mm loads have good street results?
Winchester Ranger 127-grain +P+.
Orlando PD has been using it for years.
Can you share what +p+ 9mm loads have good street results?
In addition to the +P+ Ranger 127 grain. The 9BPLE ( 115 Grn JHP+P+), which was the gold standard for a decade or more.
Some people are still mystified as to why a 357 magnum is so much more effective than a 38 Special when they use the same bullet, the magnum moves about 500 fps faster which effectively doubles the energy.
No. Nobody who follows modern terminal ballistics is the least bit mystified.
Early HP bullets were designed by shooting into water. Water causes a HP bullet to expand reliably at a lower velocity, so 357 did better than 38 and light +P 9mm did better than the slower heavier bullets. (In unobstructed shootings where the lack of penetration didn't come into play)
No. Nobody who follows modern terminal ballistics is the least bit mystified.
Early HP bullets were designed by shooting into water. Water causes a HP bullet to expand reliably at a lower velocity, so 357 did better than 38 and light +P 9mm did better than the slower heavier bullets. (In unobstructed shootings where the lack of penetration didn't come into play)
Both the 357 magnum and the 9mm +P+ work very well on people.
There are plenty of standard pressure 9mm that performs as well, without the extra recoil and blast.
Basically there is a minimum amount of energy needed to reliably both expand and penetrate enough. More power can give you a little more of one or both, but that doesn't translate to significantly increased terminal performance.
There are plenty of standard pressure 9mm that performs as well, without the extra recoil and blast.
Basically there is a minimum amount of energy needed to reliably both expand and penetrate enough. More power can give you a little more of one or both, but that doesn't translate to significantly increased terminal performance.
Are you saying that based on gelatin tests or street results?
Are you saying that based on gelatin tests or street results?
Not Todd, but rounds that perform well in the FBI tests, recommended by DocGKR perform well “in the street”... so “both”.
147gr hst
147gr golddot
124gr +p gd
All are top loads in gel testing and have performed very well in OIS.
FBI testing has been backed up by a significant amount of OIS examinations. There are no fact based reasons to question gel testing.
No pistol caliber wounds are not impressive, so the difference between the best performing 9/40/45/9+P is just not worth worrying about.
FBI testing has been backed up by a significant amount of OIS examinations. There are no fact based reasons to question gel testing.
No pistol caliber wounds are not impressive, so the difference between the best performing 9/40/45/9+P is just not worth worrying about.
Must be why I like the 357 Sig and magnum.
Not Todd, but rounds that perform well in the FBI tests, recommended by DocGKR perform well “in the street”... so “both”.
147gr hst
147gr golddot
124gr +p gd
All are top loads in gel testing and have performed very well in OIS.
Actually, they don't perform on the street any better than bullets did before the FBI protocol. I was a cop then too, people still occasionally need to be shot alot to stop them. The Cop that was just shot in Cicero, Il was shot 4 times, stayed in the fight, radioed it in.
No pistol caliber wounds are impressive.
None.
I didn't exclude 357 Sig and magnum (10mm) from that statement. I didn't include them in common service calibers because they are not common.
Anecdotal "street" performance is usually used to disregard testing that doesn't match up to ones biases.
I believe gel testing is a consistent medium to test bullet performance. I believe the experts that say actual shooting results compare well to the gel results. Gel results don't show any significant increase in wounding from magnum or +P.
MorphCross
09-18-18, 16:12
No pistol caliber wounds are impressive.
None.
Anecdotal "street" performance is usually used to disregard testing that doesn't match up to ones biases.
"But! But! All the YouBoobers that shoot meat that was thawed from previously frozen can't be wrong! Muh .40 S&W! Muh .357 Sig!"
I can't understand the level of self delusion that leads people to think what Trauma Surgeons and Coroners have been telling us for years is incorrect.
Pistol wounds make wounds the size of the bullet themselves. That'll be .357 for a FMJ or wadcutter in .38 Special or .357 Magnum or .357 to whatever the round expanded to in .38 Special or .357 Magnum.
The extra velocity means nothing as far as energy on target goes. Energy by itself isn't going to knock you out. Energy becomes a factor when the bullet reaches over 2000 fps and stretches the tissue beyond elasticity. Neither of these calibers reach that velocity.
The .357 had a better reputation because when hollow points were used of the same weight as the .38, the extra velocity made the hollow point penetrate deeper. .38's in hollow points penetrate much shallower.
The extra velocity of the .357 Magnum also penetrates hard barriers better than the .38.
No pistol caliber wounds are impressive.
None.
I didn't exclude 357 Sig and magnum (10mm) from that statement. I didn't include them in common service calibers because they are not common.
Anecdotal "street" performance is usually used to disregard testing that doesn't match up to ones biases.
I believe gel testing is a consistent medium to test bullet performance. I believe the experts that say actual shooting results compare well to the gel results. Gel results don't show any significant increase in wounding from magnum or +P.
My biases come from seeing many, many people shot over a long career as a street cop. You did not address the fact that today"s wonder bullets are no better at stopping threats than they were 30 years ago. I was working the street then too.
Pistol wounds make wounds the size of the bullet themselves. That'll be .357 for a FMJ or wadcutter in .38 Special or .357 Magnum or .357 to whatever the round expanded to in .38 Special or .357 Magnum.
That depends. Pistol rounds with significant velocity that partially fragment cause significant wounds.
My biases come from seeing many, many people shot over a long career as a street cop. You did not address the fact that today"s wonder bullets are no better at stopping threats than they were 30 years ago. I was working the street then too.
That depends. Pistol rounds with significant velocity that partially fragment cause significant wounds.
On unobstructed shots, I suspect you are correct. The biggest issue is when you need to incapacitate someone inside a vehicle. 1. older rounds did not penetrate tissue well after passing through a barrier. 2. This is often caused by fragmanting. You dont want pistol rounds to fragment if you are shooting through something.
New rounds arent wonder rounds, they just hold together, expand much more reliably, and therefore penetrate much more reliably than older/poor loads. Unless you investigate a lot of OIS involving vehicles, and look at the performance (penetrstion depth, retained weight, expansion, barriers involved, etc), you likely wouldnt notice a difference.
I'm not claiming any "wonder" in modern bullet design. Just more reliably expanding and penetrating enough, even through intermediate barriers.
So as good as you expect with your older design 357 HP's (at least for unobstructed shots), but lighter recoil and higher capacity. And of course tested through barriers as well.
On unobstructed shots, I suspect you are correct. The biggest issue is when you need to incapacitate someone inside a vehicle. 1. older rounds did not penetrate tissue well after passing through a barrier. 2. This is often caused by fragmanting. You dont want pistol rounds to fragment if you are shooting through something.
New rounds arent wonder rounds, they just hold together, expand much more reliably, and therefore penetrate much more reliably than older/poor loads. Unless you investigate a lot of OIS involving vehicles, and look at the performance (penetrstion depth, retained weight, expansion, barriers involved, etc), you likely wouldnt notice a difference.
I carried a 357 Magnum for about 20 years on the street 6 years in Ft Worth, Tx and more with the US Border Patrol. Most of the cops I worked with in the 80's and early 90's carried 357's too. The JHP's in 357 magnum penetrated cars and people is no specific order with boring regularity. When we went to the 40 with a 155 grn JHP @ 1250 fps and later @ 1200 fps it behaved in a similar manner.
I'm not claiming any "wonder" in modern bullet design. Just more reliably expanding and penetrating enough, even through intermediate barriers.
So as good as you expect with your older design 357 HP's (at least for unobstructed shots), but lighter recoil and higher capacity. And of course tested through barriers as well.
Blast and recoil are range issues to a certain extent, at least as far as the 357 magnum is concerned.
I carried a 357 Magnum for about 20 years on the street 6 years in Ft Worth, Tx and more with the US Border Patrol. Most of the cops I worked with in the 80's and early 90's carried 357's too. The JHP's in 357 magnum penetrated cars and people is no specific order with boring regularity. When we went to the 40 with a 155 grn JHP @ 1250 fps and later @ 1200 fps it behaved in a similar manner.
I was specifically talking about 9mm.
In 2018, you get your “357” performance in 9mm with the tag-along benefits of 17rd mags, less recoil, less blast/flash.
I was specifically talking about 9mm.
In 2018, you get your “357” performance in 9mm with the tag-along benefits of 17rd mags, less recoil, less blast/flash.
The +P+ 9mm is very good, but its not that good. In jello maybe.....But that is only one part of the equation. I mostly carry a 357 Sig or 40 S&W Glock. I carry a 40 at work and would carry a 9 if it was issued.
younggrasshopper
03-09-20, 10:55
My biases come from seeing many, many people shot over a long career as a street cop. You did not address the fact that today"s wonder bullets are no better at stopping threats than they were 30 years ago. I was working the street then too.
I would tend to agree. But I’d say the one caveat to your statement is the vast majority of the shootings I’ve responded to where a firearm and/or ammunition was recovered at scene were committed by someone using absolutely terrible ammunition.
Dr. Bullseye
03-09-20, 12:38
We are talking about bullets here, right? The earth has momentum caused by its movement. But we never think of this unless we are launching a rocket. Muzzle Energy is the kinetic energy of the bullet flying through the air. If you step in front of a bullet, you are going to receive all (or most--it could fly all the way through you) at once. If you step in front of the earth's momentum you never notice it because you are traveling with the earth at the same speed (unless you are entering earth's orbit from space as an astronaut, going West to East). So for our discussion and as a matter of practicality, the kinetic energy produced is a better measure.
So for our discussion and as a matter of practicality, the kinetic energy produced is a better measure.
Neither is useful. Energy does not tell us anything useful about terminal performance.
Examining the damage done to something that closely simulates tissue is how terminal performance is determined.
Neither is useful. Energy does not tell us anything useful about terminal performance.
Examining the damage done to something that closely simulates tissue is how terminal performance is determined.
I agree. Our issued duty ammunition had a high calculated energy factor, but did not perform well on people I've seen shot with the cartridge.
turnburglar
03-10-20, 10:12
The rules of a gun fight are as follows:
1. shot placement
2. shot placement
3. shot placement
4. capacity
5. expanding
6. fragmenting
7. follow up with additional shot placement
That's it.
Is it the greater power factor of .458 (600 kgr-ft/s) vs .308 (463 kgr-ft/s)? Or is it something else -- sectional density? Bullet weight and diameter? Expansion and penetration? What am I missing here?
Neither of those in isolation gives terminal performance info. End the day, that's the terminal ballistics of the bullet: velocity, mass of the projectile, sectional density, etc, are variables dictating that behavior in tissues: how much actual damage is done. I believe that's an accurate, if not overly simplified, summary of it.
Dr. Bullseye
03-10-20, 14:07
The imparting of kinetic energy to an object is measured in joules
https://en.wikipedia.org/wiki/Joule
and is exactly what we are talking about.
The joules imparted from an AK round is higher than an AR round, for instance.
The imparting of kinetic energy to an object is measured in joules
https://en.wikipedia.org/wiki/Joule
and is exactly what we are talking about.
The joules imparted from an AK round is higher than an AR round, for instance.
A 115gr 9mm is about 400ft-lb
A 147gr hst is about 300ft-lb
Does that mean 115gr fmj is more effective?
The joules imparted from an AK round is higher than an AR round, for instance.
And provides nothing useful to compare terminal performance.
It is a mistake to dismiss energy as being unimportant. Terminal performance/FBI tests are valuable in selecting the best load for a given cartridge, not for selecting the cartridge itself.
The best performing round in a .380 ACP (200 ft/lbs) is not going to exhibit the same terminal effect as the best performing 9x19 (330+ ft/lbs).
Unfortunately, energy calculation favors velocity, so you have to take it with a grain of salt - the 7.62x25 (Tokarev) cranks out 500+ ft/lbs of energy while delivering sub-optimal terminal performance.
Andy
Mass and velocity can be useful to help predict terminal performance, but if the terminal performance is already known, then external predictors are not important.
Gel tests can certainly be used to compare different calibers; we can, for example, conclude that X 9mm loading performs better than Y .40 S&W loading, regardless of energy or momentum figures. One could also guess that the best performing .40 loading would probably have better terminal performance than the best 9mm loading, and they'd likely be correct - but without testing to actually verify this, it remains just a guess.
Unfortunately, energy calculation favors velocity, so you have to take it with a grain of salt - the 7.62x25 (Tokarev) cranks out 500+ ft/lbs of energy while delivering sub-optimal terminal performance.
Your own "unfortunate" reality completely undercuts the premise that energy numbers are useful.
That is why we are even having this debate. Because energy numbers don't reflect what we see in actual terminal performance, or what we want to see.
Power factor was made up so the mighty 45 APC single stack could compete against the wimpy but double stack 9mm.
Taylor made up the weighted KO formula to try to match up to hunting results with the single expanding bullet design of the time (and the lore of some calibers).
I still say there is no good reason to look at energy numbers when we can simply compare gel results of 9mm, .380, and 7.62x25 to make an informed decision.
Your own "unfortunate" reality completely undercuts the premise that energy numbers are useful.
That is why we are even having this debate. Because energy numbers don't reflect what we see in actual terminal performance, or what we want to see.
Power factor was made up so the mighty 45 APC single stack could compete against the wimpy but double stack 9mm.
Taylor made up the weighted KO formula to try to match up to hunting results with the single expanding bullet design of the time (and the lore of some calibers).
I still say there is no good reason to look at energy numbers when we can simply compare gel results of 9mm, .380, and 7.62x25 to make an informed decision.
Where as modern 9mm JHPs perform consistently well, .380 does not (at least last time I checked) and I never looked at 7.62x25 mm or considered it myself.
I want to believe because it means my bullet choices matter more and I have more control. And i forget sometimes that it hardly matters.
A agree that we can largely not worry about theories when we have scales, chronograph's, and testing mediums of all kinds to see what really happens.
I've been thinking for awhile that the common thought that bullet design / cartridge power (within a certain realm) has more to do with "stopping power" than "killing power" is wrong. People often say, "sure, that bullet will kill, too, but this one is more likely to stop them quickly."
I believe the truth is bullets that do "better" in our test mediums aren't any more likely to "stop" but are probably better at killing. (Sooner or later)
I dont think the common service calibers are any better at "stopping" than weaker calibers. But they are better at keeping up that performance at greater distances and through barriers (For better or worse) and at killing the person shot. (For better or worse)
My criteria now is only to use HP's for the purpose of preventing over penetration as long as testing shows that bullet will normally both parachute and penetrate "enough".
"Stopping the attack quickly" only comes from nervous system damage and luck / chance / fortitude of the person shot.
More rounds on target quickly with enough penetration is the way. (After awareness, avoidance, tactics, etc)
Unfortunately, energy calculation favors velocity, so you have to take it with a grain of salt - the 7.62x25 (Tokarev) cranks out 500+ ft/lbs of energy while delivering sub-optimal terminal performance.
Andy
Well, pretty good performance for a soldier at war in an urban area fired from a sub-machine gun but yes, if we're talking about handgun use in the US and fmj you're right. 😁
Well, pretty good performance for a soldier at war in an urban area fired from a sub-machine gun but yes, if we're talking about handgun use in the US and fmj you're right. 😁
Since were on that...Hornady may as well make a 7.62x25 Critical Defense load. They have just about every other caliber and I think they'd make money on it. Low flash powder, low recoil load, small / pointed meplat for the Tok's. Betcha they do it.
I want to believe because it means my bullet choices matter more and I have more control. And i forget sometimes that it hardly matters.
A agree that we can largely not worry about theories when we have scales, chronograph's, and testing mediums of all kinds to see what really happens.
I've been thinking for awhile that the common thought that bullet design / cartridge power (within a certain realm) has more to do with "stopping power" than "killing power" is wrong. People often say, "sure, that bullet will kill, too, but this one is more likely to stop them quickly."
I believe the truth is bullets that do "better" in our test mediums aren't any more likely to "stop" but are probably better at killing. (Sooner or later)
I dont think the common service calibers are any better at "stopping" than weaker calibers. But they are better at keeping up that performance at greater distances and through barriers (For better or worse) and at killing the person shot. (For better or worse)
My criteria now is only to use HP's for the purpose of preventing over penetration as long as testing shows that bullet will normally both parachute and penetrate "enough".
"Stopping the attack quickly" only comes from nervous system damage and luck / chance / fortitude of the person shot.
More rounds on target quickly with enough penetration is the way. (After awareness, avoidance, tactics, etc)
Rounds that expand and penetrate deep enough to reach vitals is the most situations will result in the quickest incapacitation.
Unless a switch (CNS) is hit, you have to have blood pressure drop(ignoring psycological stops/drops). Expanding rounds through the heart, lungs, liver, or major arteries produce much quicker pressure drop than fmjs.
Bonded rounds (and hst) hold together through barriers (including extremities) allowing better penetration.
Expansion is key, because it tears tissue, as opposed to tissue stretching around the round (how many bow hunters use field points? How far will a heart shot deer run if a field point is used?)
Looking at energy, all service pistol rounds cause insignificant temp cavity damage.
The best rounds have to have enough energy to expand reliably and penetrate enough to reach vitals reliably. All normal rounds have enough energy to achieve this, and the limiting factor is the bullet design (see above). With a given energy, you have ‘x’ expansion and ‘y’ penetration. You can increase one, but the other will decrease with a given energy. Mass is another variable that will influence this. As weight goes down, so will penetration, due to the calculations of momentum.
Energy, or even momentum, in and if itself, when discussing service pistol calibers, is useless.
Any measure is useless except for the quantified results.
Gel testing (calibrated ordinance gel) has show the best way to measure load performance with a statistical correlation to real world results.
Duncan MacPherson's book lists different crush diameter coefficients for different shapes of bullets, but I think this may be largely speculatory, as examination of entrance wounds seems to show that diameter scales pretty closely with bullet diameter.
Flatter meplats and sharper edges do likely make a difference as the bullet slows down near the end of its track, and then a round projectile is more likely to push structures aside rather than cut or crush them. This could certainly be the case for relatively slow moving arrows. Earlier on though I would guess that most bullets incapable of temporary cavitation damage will crush a path about their size.
The main benefit to expansion it seems is the increase in frontal area, which, when viewed from a relative percentage standpoint, can be quite large.
So far as lethality is concerned...I would guess that increases in lethality would scale pretty well with increase in incapacitation ability in the short term. In the long term, however - that is to say, in regards to bullets that are not quickly fatal - there may be less difference than expected between a bullet that does more damage and a bullet that does less damage. The body has a number of compensatory mechanisms for adjusting to localized (and systemic) blood loss that can be quite effective, given time to work.
Rounds that expand and penetrate deep enough to reach vitals is the most situations will result in the quickest incapacitation.
Unless a switch (CNS) is hit, you have to have blood pressure drop(ignoring psycological stops/drops). Expanding rounds through the heart, lungs, liver, or major arteries produce much quicker pressure drop than fmjs...
...Gel testing (calibrated ordinance gel) has show the best way to measure load performance with a statistical correlation to real world results.
When it comes to non-service scenarios I don't think the blood pressure loss caused stops come in to play often if the nervous system or psychological stop doesnt happen. It still takes several seconds during which the BG can fight if he wants. Even the deer often run after complete penetration with hunting tipped arrows.
As for the gel testing, its very helpful of course, but i dont think there is enough information to say there is a "statistical correlation with real world results". (For quick stops)
I guess my point is (individual) .32, .380, and .38 bullets are closer in performance (quick stops) to a service caliber jhp than we often think and the service caliber jhp's aren't much, if any more effective (at quickly stopping) than a lead ball from a .44 / .50 lead ball or .45 colt LFN.
But the service calibers are better at penetrating barriers, over penetrating (fmj or failed jhp's) people, performing at longer distances, and killing / killing more quickly.
When it comes to non-service scenarios I don't think the blood pressure loss caused stops come in to play often if the nervous system or psychological stop doesnt happen. It still takes several seconds during which the BG can fight if he wants. Even the deer often run after complete penetration with hunting tipped arrows.Consider that it only takes a minor loss of blood pressure via orthostatic hypotension (i.e. standing up and getting dizzy) to immediately induce effects that would be highly detrimental in the context of a gunfight. While the body can tolerate surprisingly large amounts of blood loss over longer period of time, it appears to be far less adept at handling very rapidly inflicted trauma.
Further note that CNS shots comprise a minority of hits, and it's estimated only about half of incapacitations are psychological - something must account for the remainder.
Comparisons between deer and people are not always helpful; deer are more durable in some ways, more fragile in others. But if we are going to foray into effectiveness on quadrupeds, it might be noted that there were occasions during the Thompson-LaGarde tests where cows weighing much more than humans collapsed immediately after being shot multiple times in rapid succession - and only when shot multiple times in rapid succession. Autopsies displayed a lack of CNS damage.
As for the gel testing, its very helpful of course, but i dont think there is enough information to say there is a "statistical correlation with real world results". (For quick stops)
"Quick stops" are too variable to try to model or quantify. So I choose a load that performs reliably for the worst case. A service caliber and HST, GoldDot, ect, if possible. If you must go smaller pick penetration rather than expanding.
As far as actual damage in a shooting vs gel, DocGKR told me is is well studied in OIS shootings.
I don't put much weight on energy calculations or Emergency Room doctor opinions. I had the opportunity to investigate a number of shooting incidents where I interviewed the shooter and was able to ask what the attacker did immediately after being shot. I interviewed Emergency Room doctors who treated people who were shot. I also attended autopsies and reviewed other investigative reports. Most of the attackers were shot with handguns. I've heard some wild opinions from ER doctors and surgeons that were contrary to what actually occurred and could have hurt the shooter in criminal court.
There is some use for collecting scientific data, but I have never been attacked by a gelation block or had an ER doctor present when I was attacked. I've seen people in the field within minutes after they were shot. I select my carry ammunition based on documentation of rapid incapacitation.
This will undoubtedly raise a few hackles, let the fur fly.
Read what is available to you, but filter out the B.S. before selecting a defensive pistol cartridge.
"Quick stops" are too variable to try to model or quantify. So I choose a load that performs reliably for the worst case. A service caliber and HST, GoldDot, ect, if possible. If you must go smaller pick penetration rather than expanding. ~ SNIP
How do you define service caliber if you don't use velocity, energy, or bullet weight to describe potential performance?
It's an academic question, I admit.
This was specifically the work of terminal ballistics experts, not ER docs.
It should be fairly obvious that an ER doc is poorly suited to compare wounds to gel results. They have other priorities.
How do you define service caliber if you don't use velocity, energy, or bullet weight to describe potential performance?
Ummm, calibers that are in common service use?
If a new caliber comes out I want to see how it does in FBI testing. I have no interest or knowledge of how many ft/lbs or power factor 327 Federal has.
I don't put much weight on energy calculations or Emergency Room doctor opinions. I had the opportunity to investigate a number of shooting incidents where I interviewed the shooter and was able to ask what the attacker did immediately after being shot. I interviewed Emergency Room doctors who treated people who were shot. I also attended autopsies and reviewed other investigative reports. Most of the attackers were shot with handguns. I've heard some wild opinions from ER doctors and surgeons that were contrary to what actually occurred and could have hurt the shooter in criminal court.
There is some use for collecting scientific data, but I have never been attacked by a gelation block or had an ER doctor present when I was attacked. I've seen people in the field within minutes after they were shot. I select my carry ammunition based on documentation of rapid incapacitation.
This will undoubtedly raise a few hackles, let the fur fly.
Read what is available to you, but filter out the B.S. before selecting a defensive pistol cartridge.
You’re the only one to bring up ED Docs so far.
Gel exists so we don’t have to go around shooting hundreds of people to test a new cartridge. Its job is to be consistent.
You’re the only one to bring up ED Docs so far.
Gel exists so we don’t have to go around shooting hundreds of people to test a new cartridge. Its job is to be consistent.
You make a good point about using gelatin instead of alternative testing mediums.
I had the opportunity to be present when gelatin testing was conducted on several handgun and rifle cartridges. One cartridge that performed great in the field did not do well during gelatin testing. Another cartridge that performed beautifully in gelatin did not perform that well in the field.
There is a lot of information available about cartridge performance, especially on the internet. Some of the information is good and some not so good.
We can expect greater variation in actual tissue as compared to gel; it takes a large sample size to confidently determine whether a clear correlation exists. On my end, I personally trust that IWBA and friends have done their due diligence.
I do have a question. When you say that a cartridge performed beautifully in gelatin but not in the field, do you mean that the bullet behaved differently in the different mediums - that it did not expand or penetrate as well as it should have? Or do you mean that this bullet was deemed to have an ideal set of characteristics by some certain criteria, but in practice was not very effective?
Some manufacturer gel testing seems funky (several of Hornady's rifle tests come to mind), sometimes QC for production is not the same as it is for select samples (e.g. Gold Dot G2), and sometimes agencies have a scoring index that seems rather arbitrary. For example: To my knowledge, the FBI scoring equation weights penetration through all barriers the same in that it combines each sample into an average; it doesn't matter whether the bullet does 14 inches through heavy clothing and 9 inches in auto glass, or 14 inches in auto glass and 9 inches through heavy clothing. It also does not award any additional points for expansion over 0.625 inches, which potentially biases the test against certain bullets that can achieve well in excess of that.
If you'd also have any insights you'd like to share about which particular loadings perform well and which don't, I'd certainly be interested in hearing them.
We can expect greater variation in actual tissue as compared to gel; it takes a large sample size to confidently determine whether a clear correlation exists. On my end, I personally trust that IWBA and friends have done their due diligence.
I do have a question. When you say that a cartridge performed beautifully in gelatin but not in the field, do you mean that the bullet behaved differently in the different mediums - that it did not expand or penetrate as well as it should have? Or do you mean that this bullet was deemed to have an ideal set of characteristics by some certain criteria, but in practice was not very effective?
Some manufacturer gel testing seems funky (several of Hornady's rifle tests come to mind), sometimes QC for production is not the same as it is for select samples (e.g. Gold Dot G2), and sometimes agencies have a scoring index that seems rather arbitrary. For example: To my knowledge, the FBI scoring equation weights penetration through all barriers the same in that it combines each sample into an average; it doesn't matter whether the bullet does 14 inches through heavy clothing and 9 inches in auto glass, or 14 inches in auto glass and 9 inches through heavy clothing. It also does not award any additional points for expansion over 0.625 inches, which potentially biases the test against certain bullets that can achieve well in excess of that.
If you'd also have any insights you'd like to share about which particular loadings perform well and which don't, I'd certainly be interested in hearing them.
The Winchester .38 Special +P Lead HP bullet did not expand in bare gelatin in two attempts. It was used in one local shooting incident and the round expanded well and had sufficient penetration after being fired from a 4" revolver. The attacker was quickly incapacitated. A 9mm 115g +P+ cartridge had great expansion and decent penetration in gelatin, but people I saw shot with it had wounds that passed all the way through the torso. The exit wounds were the same size as the entrance wounds.
I witnessed .38 Special, 9mm and .40 S&W Gold Dot HP ammunition shot into gelatin and it got the same penetration and expansion as I've seen posted on the manufacturer's website. I have not seen anyone who was shot with the Gold Dot HP cartridge.
As a side note, if you are involved in a shooting incident, never, ever talk about the incident with EMT's, Paramedics and especially hospital personnel. If you require treatment, provide information pertinent to treatment and nothing else. I once heard an ER doctor say about a shot suspect "they didn't have to shoot him this many times to stop him. One shot should have done the job." The same doctor was interviewed after treating someone who died in the ER as a result of a motorcycle accident. The motorcycle rider's femoral artery was severed and he bled to death. The doctor told the newspaper reporter "if he had been wearing a helmet, he would still be alive."
Choose your ammunition carefully and choose your words carefully.
Everything ive read from docgkr indicates that you should consider the 4 main tests as a whole, and that the 4ld test most accurately replicates what happens in ois. That would/could explain the 115g 9mm, not sure about the 38spl.
A 9mm 115g +P+ cartridge had great expansion and decent penetration in gelatin, but people I saw shot with it had wounds that passed all the way through the torso. The exit wounds were the same size as the entrance wounds.
Bare gel or 4ld?
Bare gel or 4ld?
Both bare gel and 4 layer denim.
... It also does not award any additional points for expansion over 0.625 inches, which potentially biases the test against certain bullets that can achieve well in excess of that...
.
Typical government testing, eh?
Someone or group makes a decision then creates a "test" or "bid competition" to make it look honest knowing exactly what the result is GOING to be.
I'd wonder if the peculiarities going on with the .38 HP and 115 gr +P+ can be largely attributed to lot variation. This was kind of what I was going at with the mention of Gold Dot G2; it expanded consistently in FBI testing but often failed to mushroom when the first mass produced lots actually made it to the shelves. As I recall it was pulled from the commercial market and was not re-released until some time later.
I think 230 gr Ranger-T may have had some of the same going on, at least in the past, though not nearly as bad. Its "standard" performance is pretty close to HST, but is not as consistent.
Another possible contributor was that it was actually the FBI heavy clothing test being used for the 115 gr +P+, and not the more stringent IWBA 4LD test.
Typical government testing, eh?
Someone or group makes a decision then creates a "test" or "bid competition" to make it look honest knowing exactly what the result is GOING to be.While they may have changed the equation at some point, I believe the formula was composed back in the early 90s or so. To be fair, at the time, a bullet that averaged 0.625" across the 6 tests would have been very impressive.
Still, the method of points assignment does seem questionable to me. I suspect that the significance of low variation in penetration across all barriers - which is, to some extent, independent of whether the bullet actually penetrates adequately - played a part in the selection of CD over HST. And the rather modest importance placed on very large expansion might have been used to support the FBI's assertion that modern 9mm loads are performing on par with modern .45 loads...looking at the bare gel, 4LD, and auto glass data, a person less restrained by this sort of boxed thinking might observe that 230 gr +P HST achieves similar penetration to 147 gr HST while affording approximately 60% more frontal area. But by the FBI equation, I would guess they score pretty much the same.
For the mathematically inclined, I chronographed the 9mm 115g HP +P+ using a pistol with a 4" barrel. Average Velocity at 15 feet from the muzzle was 1,340 fps.
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